BIOBRIEF

Lateral Ridge Augmentation in the Posterior Mandible

Dr. John M. Sisto

THE SITUATION

A 70-year-old female in good health presented with a fracture of tooth #19 which is the distal abutment for a four-unit bridge tooth #19-22, with pontics in the #20 and #21 positions. With the loss of the bridge, the patient desired a fixed prosthetic replacement. A bridge from tooth #22 to an implant placed at the #18 position was not deemed mechanically sound. She opted for implant placement at positions #19, #20 and #21 following lateral ridge augmentation with autogenous bone and Geistlich Bio-Oss® contained with a Geistlich Bio-Gide® membrane.

THE RISK PROFILE

Low RiskMedium RiskHigh Risk
Patient’s healthIntact immune system Light smokerImpaired immune system 
Patient’s esthetic requirementsLowMediumHigh
Height of smile lineLowMediumHigh
Gingival biotypeThick – “low scalloped”Medium – “medium scalloped”Thin – “high scalloped”
Shape of dental crownsRectangularTriangular
Infection at implant sightNoneChronicAcute
Bone height at adjacent tooth site≤ 5 mm from contact point5.5 – 6.5 mm from contact point≥ 7 mm from contact point
Restorative status of adjacent toothIntactCompromised
Width of tooth gap1 tooth (≥ 7 mm)1 tooth (≤ 7 mm)2 teeth or more
Soft-tissue anatomyIntactCompromised
Bone anatomy of the alveolar ridgeNo defectHorizontal defectVertical defect
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THE APPROACH

A subperiosteal flap with a mid-ridge incision was performed with anterior and posterior releasing incisions which were placed the distance of one tooth mesial and one tooth distal from the graft site. The posterior releasing incision allowed for exposure of the ramus for harvesting of the autologous bone. The grafted site was allowed to heal for a period of 8 months at which time the implants were placed. Abutment connection occurred 4 months following implant placement.

CT scan showing insufficient bone width for implant placement < 4mm.
Initial incisions on the midcrest of the ridge were performed for full-thickness flap preparation.
Four mucoperiosteal flaps were done with vertical releasing incisions and interosseous holes created to stimulate bone formation (RAP phenomenon).
Harvesting of the autologous cortical bone from the lateral surface of the ramus, utilizing the Geistlich Micross.
Geistlich Bio-Oss® granules mixed with harvested autologous bone chips.
Geistlich Bio-Oss® and autologous bone mixture was placed and covered with Geistlich Bio-Gide®. Pins and screws were utilized for fixation to provide primary stability.
Re-entry 8 months post-grafting: sufficient bone has been regenerated to place implants in the desired positions.
Follow-up at the time of implant uncovering and placement of the healing abutments, (4 months post- implant placement). All implants were successfully reverse torqued at 20ncm.
At re-entry eight months post-grafting, the width of the bone had increased significantly and measured 7.46mm at position #21.

“A bone graft was required to augment the ridge, a CBCT scan was performed prior to surgery to determine bone volume and the amount of bone required to graft.”

THE OUTCOME

Following 8 months of healing, the augmented site showed sufficient bone width that was assessed with a CT scan. After examination, it was determined that the bone width was adequate for implant placement in the desired position to allow an esthetically pleasing and functional outcome for the patient.

The use of Geistlich Bio-Oss® in combination with autogenous bone provides an excellent recipient site for the placement of dental implants and long-term maintenance of bone volume for implant survival.”

Dr. John M. Sisto

The Geistlich Micross is essential in harvesting bone from the lateral ramus in an efficient and stress-free manner.”

Dr. John M. Sisto

Dr. John M. Sisto

Dr. John M. Sisto received his Doctorate in Dental Surgery degree from Loyola University and completed his residency and certification in Oral and Maxilofacial Surgery at the Cook County Hospital in Chicago. Dr. Sisto was the Director of Residency Education at Cook County Hospital from 1985 to 2010 and started the residency program in oral and maxillofacial surgery in 1990. He held teaching positions at both Northwestern and University of Illinois Dental schools as a clinical assistant professor, and also at Northwestern Medical School. He was the Division Chief of Oral and Maxillofacial Surgery at Cook County Hospital and Chairman of Dentistry at Resurrection Medical Center. Dr. Sisto has published papers on dental implant surgery, trauma surgery, orthognathic surgery and maxillofacial infections. He has lectured both locally and nationally at various educational forums.